Expansion-bolt.



W. C. YEATMAN.

EXPANSION sou. APPLICATION FILED SEPT-23, 19H.

L16%3QQ, Patented Dec. 14, 1915.

with

WALTER C. YEATMAN, OF CHICAGO, ILLINOIS.

EXPANSION-BOLT.

Specification of Letters Patent.

Patented Dee. 1d, Itlfllfi.

Application filed September 23, 1914:. Serial No. 863,170.

To all whom it may concern:

Be it known that I, WALTER C. YEATMAN, citizen of the United States, residin at, Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Expansion-l3olts; and I do hereby declare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to expansion bolts, its general object being to provide a simple and cheaply constructed appliance of this kind which may be easily and quickly manipulated for affording an efiective and positive fastening.

More detailed objects of my invention are to equip an expansible shell and a tapered expander for the same with means for interlocking the shell and expander so that the shell may readily be inserted to the desired position in a wall or floor by simply manipulating the bolt threaded to the expander; to provide means for releasing said interlocking when the shell is being expanded, so that the interlocking will not interfere with the free expansion of the shell; to provide means for interlocking the shell with the bore of the wall or floor so as to prevent a" withdrawal of the shell when the latter is being expanded; and to provide means for causing a considerable portion of the length of the expanded shell to engage the walls of the bore within which it is positioned.

Other objects will appear from the following specification and from the accompanying drawings, in which: a

Figure 1 is a section through a portion of a wall showing my expansion'bolt when first inserted in a bore within said wall. Fig. 2 is a similar view showing the bolt partially expanded. Fig. -3- is an enlarged elevation of the plug of Fig. 1, together with a fragmentary section of the end of the shell normally interlocked -therewith. Fig. 4 is a similar View "the shell when further expanded by the Fig. 6 is a transverse section plug. through Fig. 1- along the line 66. Fig. -7- is an enlarged fragmentary exterior View of the shell, showing the pyramidal formations thereon.

In the embodiment of the drawings, my invention is shown as comprising a tubular shell 1 equipped for a considerable portion of its length with slots 2 extending from the rear end of the shell 1 longitudinally of the latter, the said slots being preferably formed simultaneously by means of a pair of parallel circular saws. The bore of the said shell 1, which is otherwise cylindrical, is flared at its rear end as shown in Fig. 4:, and is equlpped near its said rear end with a recess 3 presenting a rear wall substantially at right angles to the axis of the shell. For expanding the said shell 1, which is rendered circumferentially expansible by the slots 2, I provide a plug 4: comprising a main frusto-conical portion equipped at its forward end with a radially projecting bead 5 adapted to be seated in the said recess 3 of the shell, the contracted part of the main portion immediately back of the said bead being substantially equal in diameter to the bore of theshell 1, thereby permitting the resiliency of the slotted portions of the said shell to force the latter into their said interlocking engagement (as shown in Fig. 3-) when the bolt is not in use. Vhile both the head 5 and the recess 3 may be varied considerably in shape, I preferably make the recess 3 of a sufficient length so that its forward end will clear the bead 5 when the shell 1 is being expanded by a'relative longitudinal movement of the plug 4:, as shown in Fig. -4:. I also preferably equip the plug 4 at its rear end with a substantially cylindrical portion 6 adapted to engage the bore of the shell 1 forwardly of the said recess 3 when the plug lhas been moved still farther than in Fig. 4, as for example in Fig. 5.-

The plug 4 is equipped along its axis with the usual female thread to fit a bolt 7, which bolt is provided with a suitable head 8 accessible from outside the wall and adapted both to afford a means for rotating the bolt and to afford a shoulder for engaging the object, such as a plate 9, which is to be secured tothe wall 10. It will be evident from Figs. -1 and -3- that as soon as the plug 4 is normally interlocked with the shell 1, and as soon as the bolt 7 has a threaded connection with the plug 4, the entire appliance may readily be inserted into the bore 11 of the wall or fioor, asthe shell will not be free to slide with respect to the plug. Heretofore, in using expansion shells equipped with tapering plugs, it has usually been necessary to provlde some means for forcing the shell to follow the plug, as the bolt would readily carry the plug to its proper position within the wall, while the rough surfaces of the bore were apt to. catch the rear end of the shell so as to stop the. latter in a position leaving a considerable gap between the conical surfaces of the plug and the rear end of the shell. The gap thus afforded permitted the entry of par-.

' with the plug, I cause the latter substantially to seal the rear end of the shell, so that I not only avoid the additional labor required for forcing the shell into the desired position,but also avoid the difliculties due to the entry" of foreign materials into the bore of the shell. Upon rotating the bolt,

thefrictional engagementbetween the plug and the shell will tend to prevent the plug from rotating, whereupon the'threaded engagement of the plug with the shank of the bolt will cause the latter to draw the plug forwardly into the shell.

In so doing, the taper of the plug will cause the latter both to expand the shell and toengage the latter with anincreasing friction. However, since the plug is rotatable with respectto both shank and shell, the frictional engagement of the plug with the bolt will cause the latter to rotate the plug to some extent. Consequently, this differential frictional engagement of .the plug with the shankand shell will cause a rotation of the bolt to move the plug with a gradually advancing spiral motion, thus enabling the plug to be drawn farther and to effect a greater expansion of the shell with a given amount of power applied to the bolt than would be possible if the plug were not able to rotate within the shell.

To avoid. a forward sliding of theshell when the bolt 7 is rotated so as to draw the plug 4 forwardly, I equip the shell 1 for a considerable portion of its length with raised projections 12, the latter being preferably 1n the shape of pyramids presenting forward edges substantially at right angles to the axis of the shell and presenting in: clined surfaces toward the rear of the shell. It will be evident fromFig. -3 that the inclined surfaces of the projections will readily ermit the shells tobe slid into a closely tting bore, but that the said for ward surfaces of the projections will pre-- vent a motion of the shell in the opposite direction. Consequently, the shell will readily be anchored at the desired position in the wall as soon as the bolt 7 is rotated,

thereby ermitting the said rotation of the bolt to raw the expand the shell.

If the wall equipped with the bore housing my appliance is of relatively soft .material, as in Fig. 2-, the initial expansion may cause the extreme rear ends of the shell to dig into the sides of the bore before the plug has an opportunity of expanding a relatively longer portion of the shell. However, if the Wall is of a relatively unyielding material, the taper of the plug will gradually cause the expansible portion of the shell to engage the bore of the wall for an increasingly greater portion of the length of the shell, in doing which the said cylindrical portion 6 of the plug will engage the bore of the shell forwardly of the recess 3, as shown in Fig. 5.' e

It will be evident from the above that the use of my expansion bolt involves merely the boring of a hole of suitable size and the insertion of the assembled members (as plug 4 forwardly so as to shown in Fig. 1) without requiring any particular attention or manipulation of the shell with respect to the plug or expander, as the cooperating formations upon these two elements will normally interlock the same. -However, the said interlocking will at no time interfere with a rotation of the plug with respect to the shell, so that under certain conditions the plug may slip circumferentially Within the shell, thereby permitting it to be advanced with a helical motion and thus affording a greater leverage for the power applied to the bolt. So also, the interlocking will not interfere with a tilting of the bolt out of axial alinement with the shell to compensate for irregularities in the bore housing the shell. Moreover, this interlocking of the shell with the plug enables me to insert these elements together into the bore'which is to receive the same, and thereafter screwing the bolt into the plug, making a convenient method of using such bolts While I have shown my appliance as in-' cluding a shell rendered circumferentially expansible by means of a pair of parallel saw-cut ends, I do not wish to be limited to this or other details as herein disclosed, it being-evident that these might be varied considerably without departing from the spirit of my invention as set forth in the appended claims. I

I claim as my invention:

1. An expansion bolt comprising a member having a threaded shank, a tube of resilient material housing said threaded shank and equipped at its rear end with at least meaeaa I one slot extending longitudinally of said tube, and an exteriorly tapered plug threaded upon said shank and positioned with its smaller end within the bore of the rear end of the tube, said plug rotatable with respect to the tube and having a differential frictional engagement with the shank and tube for causing a rotation of the shank to move the plug forwardly within the tube with a spirally advancing motion, the said smaller end of the plug and the rear end of the tube being equipped respectively with bead and groove formations normally interlocking said tube and plug to prevent a movement of the plug out of the rear end of the tube, the resiliency of said tube permitting the rear end thereof to be expanded by the said forward movement of the tapering plug to bring the said formations on the tube and plug out of their said interlocking engagement.

2. In an expansion bolt, the combination with a threaded shank, of a tube of resilient material partially housing said shank and slotted at one end, and a tapering plug threaded upon said shank and having its smaller end disposed within the said slotted end of the tube, the said tube equipped upon its interior at its said slotted end with an annular recess, the said plug equipped at its forward end with a bead housed by the said recess, the resiliency of the tube normally maintaining said recessed portion of the tube in its said relation to said bead, the width of the said recess being greater than the width of the said bead and the said widths being relatively so proportioned to the taper of the plug that the expansion of the slotted end by the entering of the plug thereinto will permit the said bead to pass freely beyond the forward end of the said recess.

3. An expansion bolt comprising a member having a threaded shank, a tube housing being equipped upon its outer surface with substantially pyramidal projections having axes disposed radially of the axis of said tube and each thereof presenting a forward surface substantially at right angles to the axis of the tube.

4. An expansion bolt comprising a member having a threaded shank, a tube housing said shank and expansible at its rear end, an exteriorly tapered plug threaded upon the shank and having its forward end smaller than the said expansible end of the tube, said plug frictionally engaging the interior of the tube, and means for interlocking the plug and the expansible end of the tube when the latter is unexpanded, said means permitting the plug to be rotated within the tube by the frictional engagement of the plug with the threaded shank when the latter is rotated; the frictional engagement of the tubewith the plug retarding the said rotation of the latter so as to cause the rotating of the shank to screw the latter through the plug, thereby drawing the plug forwardly within the tube; the taper of the plug causing the latter to expand said end of the tube when thus drawn forward and the said interlocking means being so disposed as to be released by the said expanding of the tube.

In testimony whereof I have signed my name in presence of two subscribing'witnesses.

WTER C. YEATMAN.

Witnesses:

ALBERT SCHEIBLE, C. C. BRINKERHOFF. 

